LARVAL FEEDING OF THE WESTERN CORN ROOTWORM (DIABROTICA VIRGIFERA VIRGIFERA

LECONTE) ON ROOTS OF SEVERAL WEEDS AND ITS EFFECT ON CROP ROTATION

József Takács, Péter Balogh, Miklós Nádasy and Lénárd Márton

University of Veszprém, Georgikon Faculty of Agriculture, Department of Agricultural Entomology, Keszthely, Hungary

Larval feeding of WCR

Questions

• Is it a monophagous pest?

• Can larvae feed on roots of other plants?

• Monocot vs. dicot weeds?

• Mortality on alternative hosts?

Is it a monophagous pest?

REALLY???

Is it a monophagous pest?Is it a monophagous pest?

Dicot weedsDicot weeds

Is it monophagous?

Really???

Danger!?!

• Developing on alternative roots

Development of WCR larvae is not possible on alternative host plants.

Mortality is so high!

BUT!!!

Weeds are suitable for larvae as

survival nutriments!

Host plant Mortality /20 larvae Change instars Day of death 3.day 6. 9. 12. 15. ZEAMA L1 0 - - - - 3-5. day 11.

L2 0 1 0 - - 7-11. day 14.

L3 0 0 0 2 2 - 21.

SORHA L1 0 6 8 4 3 - 15.

L2 0 4 4 7 5 -

L3 0 0 4 9 7 -

ECHCG L1 0 0 3 2 1 - 18.

L2 0 0 1 0 2 - 19.

L3 0 0 0 3 2 - 18.

DATST L1 0 0 0 1 0 - 21.

L2 0 0 1 2 0 - 21.

L3 0 2 1 3 5 - 17.

AMARE L1 0 0 1 1 1 - 21.

L2 0 6 5 2 3 - 16.

L3 0 0 12 5 3 - 15.

Feeding on alternative hosts

Summarized• Survival nutrition on alternative roots

• Weedy cornfields!

HIGHER SURVIVAL RATIO

HIGHER DAMAGES!!!

Adult feeding on alternative host plantsAdult feeding on alternative host plants

Problems in fallow management

Weeds on fallow fields

Oviposition on weedy plots

Larval damages in next year corn

Crop rotation is one of the most effective control method!

REALLY???